21236649984 has 585 divisors, whose sum is σ = 72895222939. Its totient is φ = 6155550720.

The previous prime is 21236649943. The next prime is 21236649991. The reversal of 21236649984 is 48994663212.

The square root of 21236649984 is 145728.

It is a perfect power (a square), and thus also a powerful number.

21236649984 is a `hidden beast` number, since 2 + 12 + 3 + 66 + 499 + 84 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21236649984.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 923332597 + ... + 923332619.

Almost surely, 2^21236649984 is an apocalyptic number.

21236649984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

21236649984 is the 145728-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21236649984

21236649984 is an abundant number, since it is smaller than the sum of its proper divisors (51658572955).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21236649984 is an equidigital number, since it uses as much as digits as its factorization.

21236649984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104 (or 39 counting only the distinct ones).

The product of its digits is 4478976, while the sum is 54.

The spelling of 21236649984 in words is "twenty-one billion, two hundred thirty-six million, six hundred forty-nine thousand, nine hundred eighty-four".